After bringing Rocky Balboa out of retirement, Sylvester Stallone is eyeing an encore for his other signature character, the killing machine named John Rambo.

Stallone has gone into business with Millennium Films, Emmett/Furla Films and Equity Pictures on “Rambo IV.” So far, they’ve got a plotline and a projected budget of $50 million and will soon get a writer to draft the script. The producers are hoping Stallone will put the knife between his teeth right after he wraps “Rocky Balboa,” a film he is writing and directing for an early 2006 start.

In “Rambo IV,” John Rambo is living a quiet life as a recluse in the U.S. — until a young girl goes missing, and he returns to macho form and takes justice into his own hands. Plan is to shoot in Mexico and the U.S.

Pic will be produced by Millennium’s Avi Lerner, Boaz Davidson and Emmett/Furla principals Randall Emmett and George Furla, along with Kevin King. Danny Dimbort, Trevor Short, John Thompson, Andreas Thiesmeyer, Joseph Lautenschlager and Gerd Koechlin are exec producing.

Dimension Films once tried to mount “Rambo IV” after Bob and Harvey Weinstein rescued that title and “Total Recall” from the bankruptcy auction for Carolco Pictures. It’s not surprising that a fourth installment would be attempted: The first three combined for a worldwide gross of $610 million.